HIGH BREAKDOWN-VOLTAGE SEMICONDUCTOR DEVICE

摘要

PROBLEM TO BE SOLVED: To prevent reduction in the tolerance with respect to the transient voltage by suppressing avalanche breakdown of a second conductivity-type layer end part even in the case of a high breakdown voltage.SOLUTION: By forming a high concentration second conductivity-type layer 5 having higher impurity concentration than a second conductivity-type layer 4 in the inner side of a region in the second conductivity-type layer 4 facing a first conductivity-type buried layer 2, even in the case of a high breakdown voltage, avalanche breakdown of the second conductivity-type layer 4 end part is suppressed and reduction in the tolerance with respect to the transient voltage can be prevented.